Inflight tire gauge



Dec. 27, 1949 a UPCHURCH, JR 2,492,450

INFLIGHT TIRE GAUGE Filed Nov. 9, 1945 2 Sheets-Sheet 1 Thomas 5. qoc/urc/r J/r gwumvto't T. B. UPCHURCH, JR 2,492,450

INFLIGHT TIRE GAUGE Dec. 27, 1949 Filed Nov. 9, 1945 2 Sheets-Sheet 2 7/70/2705 5. Upcfiurch Jr grwwwfm Patented Dec. 27, 1949 UNIT ST PATENT OFFICE 2,492,450 I INFLIG'HT TIRE GAUGE. Thomas B. Ui ehprch, 'Jr Rae'ford, (i, Application November 9, 1945, Serial No. 627,563 2(31mi (01. 734-390) This invention relates toe gauging and indicating device for aircraft, such as airplanes, dirigilole balloons, and anyrtypeof air craft having landing wheels which are retractable during flight.

matic tires of aircraft so that when the pilot lands he is not aware of the fact that one of his tires is not properly inflated-9 sometimes not being inflated at all, resulting in a serious accident and much damage to the craft and, sometimes, the loss of liferofi the occupants of the craft, By having an indicating device which will contact the pneumatic casing of an aircraft when the retractable:wheels-arein retracted position, it is possible to indicate to the pilot as to whether or not the tiresof the airortaftare properly inflated.

an object of this invention to provide means for engaging the exterior of a pneumatic easing of ail-aircraft when the wheels are moved to iet a t d position which will indicate to the pilot-pf the aircraft as to whether or not the wheels are properly inflated and, if not properly inflated, {What degree of inflation is present; so that the pilot will be forewarned in making a landing as to what he faces and can take precautions by landing on one wheel and the like an thus avoid aser ous wreck.

It i ,anoth rl hi c of this inv ntion to p vide mea s for enga ing thepneumatic casing of a airo t when the wheels are in retracted position an atine t e a ou .o pr u e in the easing throu h suitable indicating means d sposed Within the= i otis cockp Eome of the objects of the invention having been stated; other Objectswill appear as the descriptionproceeds when taken in connection with the accompanying drawings, in which:

Figure 1 is; a-transverse sectional view through a portion oi an airplane, showing my invention installed;

Figure 2 awvertical sectional View taken substantially" along the line 2:4 in Figure 1, and showing the indicating means and wiring diagram schematically;

Figure '3 fsa schematic wiring diagram showing'thatwo landing wheels of an airplanehooked t o common n fo r Figure 4121s a viewsimilar tb' Figure 1, but show.- ing another gfqrm' f m invention in installed osi Flee-r i a maesd-te i w P r y sect on a sishowioet e-ge l. Well -ope ated indicating device associated with a retracted wheel of an aircraft; 7

Fi e 6 i a sc ema ic a ram showin how both, wheels of an airplane may be connected to a common caus of t type sh n Fi u 1 and 5.

Referring more specifically to the drawings, the numeral Ill indicates a portion of the frame,- work of the fuselage of an airplane, and ll indicates a portion of the wing of an airplane, both se i n, a d the us a e a d t e w e av n a suitable covering 12 which is usually of fabric or a e a plane ha aoinslrum nt boa It for various fli ht inst umen s these n um nt bein mitte th l awi e The i plane is us a y quipped w thtw o t ree etractable wh ls o ly ne o th whe s being shown n the drawin s, that ing the retractable wheel on the right side of the airplane, it being unde st od t at here is an the sim a whee located in the other wing of the airplane; and, it would also have either anose wheel or a tail Wheel, d p di upon th st le o the l ne- 'Ihese nose and tail wheels in high speed air.- planes are usually retractable also, and this-invention is adapted to be a plied to all three of he wheels if de d and certainly, to e t o m in land n whee s- Various ype o t ac abl lan n sear as? employed, and in the present instance I show a strut l5 pivotally mounted as at l5 and having a segmental gear Il secured to the shaft 16; the strut l5, shaft l6, and segmental gear Il being fixed to a h o h r o t a w n a w 18 on a worm s a .l 9 i tate b ma a ion by the pi ot byany conv nt ona m a not own the wh s :0 o atab v mo n d o the l wer end of the s ru 5, to the wit a P m c a n h e n oen b r i ed in e r t d position into a suitable pocket}; where the pneue matic' casing 2i will be removed from the slip,- sfo eam-o t e: a rpl ne- I Fi r I S w a b a ket :25 out th framework l; 0 of the airplane, and this bracket g5 is secured thereto-bysuitable bolts penetrating holes 26 in a base member 21- andalso penetrating holes 28 in the-braqret 2 5.- This base member 21 has integral therewith an uprising well 30 which a a u tabl ca 3, t re ab s s on t up end- Slidab m u ed n h w l 30 is a cylindrical member 32 in which is mounted a forked bracket 34 having a wheel 35 rotatably mounted in its lower end. The cylindrical portion 32- ha a guide r p s on o pack ng ring 1 and a o a e metalii bandsur ound n t a new this metallic band penetrating the cylindrical member 32 at one point and. having a metallic portion 49 on which the lower end of a compression spring 42 rests. This compression spring is of steel and a metallic disk 43 fits on the top of the compression spring 42. A screw 44 is threadably mounted in the cap 3| and has mounted therearound a terminal 45.

Mounted in the side wall of shell or cylindrical member 30 are three contact members 59, and 52. The contacts 59, 5|, and 52 have leading therefrom wires 53, 54, and 55. These wires lead to one of the terminals of the incandescent bulbs 56, 51 and 58. The bulb 56 is red and the bulb 51 is amber and the bulb 58 is green, which when illuminated will indicate'd'anger, caution, or safety.

To the other sides of incandescent bulbs 56, 51, and 58 wires 60, 6|, and 62 lead to a common wire 63 which wire is connected to one side of a switch 64, this being any type of switch, such 64, a wire 65 leads to a sourceof electrical energy such as a battery 66, supported on a suitable bracket 68; and from the other side of battery 56, the wire leads to the terminal 45. a

In the other form of-my invention shown in Figures 4, 5, and 6, the same result is accomplished by a pneumatic gauge instead of an electrical' indicating apparatus. In this form of the invention, like reference characters as to the conventional parts of the airplane will apply.

To the framework of the airplane there is secureda bracket 19 having a semi-annular portion TI to the lower surface of which is secured an inverted cup-shaped member 12 which preferably is of metallic or plastic material, and fitting against the outer portions of member '12 is a flexible diaphragm 14 preferably of rubber, and a ring or annular portion 75 fits against the outer edge portions of diaphragm 74 and suitable bolts 'lfi secure the annular member 15, the diaphragm 74, the upper portion 12 to the semi-annular portion ll of bracket l9. This portion 12 may be providedwith a'suitable valve 11 such as is employedin the inner tubes which fit into pneumatic casings so that if any additional air pressure is required within chamber 18, formed by diaphragm l4 and member 12, such pressure can be applied by a'suitable pump or from a source of compressed air.

Secured to the upper central portion of member 12 is a nipple 80 which is hollow and has its lower end in communication with the chamber 18. To the upper end of nipple 80 is secured a flexible tubing 8| which leads to any suitable portion of the airplane such as the instrument board I3 where it is connected to a nipple 82 which nipple has a suitable shut-off valve 83 thereon and another nipple 84 leads'into a conventional pressure gauge 85. This pressure'gauge is adapted to register the air pressure'with the wheels in retracted position in chamber 18. Normally pressure within chamber 78 would cause gauge hand 86 to rest at the point S on the gauge, indicating safety; and, if there was not sufficient pressure within the chamber 78 due to its contact with pneumatic casing 2|, then the gauge might rest intermediate between the danger point D and the safety point S at portion C for example, indicating caution. It is evident that there would have to be suflicient pressure in chamber 18 to resist upward movement of diaphragm 14 as the result of firm contact between the diaphragm 14- and the pneumatic casing-2|; however, if

pneumatic casing 2| did not have the required amount of pressure therein, then the hand 88 would not be disposed at point S on the gauge but would be disposed at a lower point on the gauge, possibly down to the point D indicating danger, if there was not sufiicient pressure within the pneumatic casing to compress the diaphragm 14 upwardly.

In the form of the invention shown in Figures 1, 2, and 3 if the pneumatic casing 2| had normal air pressure therein, then it would tend to move the cylindrical member 32 upwardly to a point where the contact ring 33 would contact the contact member 52 and a circuit would be passed through the incandescent bulb 58 which is green and which would indicate to the pilot that the casing was properly inflated. If there were some pressure in pneumatic casing 2| but not the required pressure, then the contact ring 38 would probably rest on contact 5| and this would energize bulb 51- indic-ating caution. If there were practically no pressure within casing 2|, then the parts would rest in the position shown in Figure 2 and contact ring 38 would engage contact 50 and incandescent bulb 56, which is red, would be illuminated which would indicate to the pilot that this casing was completely deflated and, therefore, could not stand the impact of a landing.

It is not necessary for the indicators in both forms of the invention to operate at all times. During flight the switch 64 can be moved to disconnected position to save battery current and, likewise, the valve 83 could be closed to cut off the pressure from thegauge if it were not desired for the gauge to be registering at all times. In :both forms of the invention, there could be (a separate indicating device for each .wheel of the airplane if desired, but if it were desired to connect .both wheels to a common indicating apparatus, then there is shown in Figure 3 how the first form of the inventionshown in Figures 1 and 2 could have both wheels connected to a common indicating device in which like reference characters apply to the left hand wheel as has been described for the right hand wheel except that the prime notation has been added and the description previously given will equally apply. It might be stated that in Figure 3, if both switches 64 and 64 were left in on position, if one wheel 2| should have low pressure therein, then that wheel would probably illuminate either the danger or ca-ution bulb, whereas, the other wheel having sufficient pressure therein would illuminate the green or safe bulb. The pilot at once would know that something was wrong and, by moving one of the switches 64 and 64 to open position it would immediately indicate which of the tires is deflated when either one of the switches 64 and 64' moved to open position.

In the schematic showing in Figure 6 also like reference characters will apply to the left hand wheel except that flexible pipe 8| and 8| would lead to a T 90 and each of the pipes 8| and 8| would have avalve 9| or 92 therein and, as long asbotn casings 2| were fully inflated, then the pointer 86 would stand on the S position; but, if one of the casings Was not fully inflated, then the pointer would stand, say, at the point shown in Figure 5. The pilot at once would know that something was wrong and, by closing valve 9|, if the pointer 851clropped back towards the danger point, he would know that it was the left hand wheel of the airplane which was not fully inflated; and, whereas, if the pointer 86 moved farther clockwise, he-would know that it was the right hand wheel which was not fully inflated and, by manipulating the valves 9! and 92 he could very quickly determine which of the casings was not fully inflated and the degree of inflation therein.

It will be noted in Figure 2 that the lower end of the shank 34 has the inverted U-shaped member 33 rotatably secured thereto by means of a screw 35. This will allow the roller 35 to swivel in case the tire is rotating when it is moved to fully retracted position. It will also be noted that in Figure 1 the casing is shown as being deflated so that a depression will be formed in it by the roller 35, thus allowing the contact 40 to make contact with contact '50 to show a red light.

In the drawings and specification there has been set forth a preferred embodiment of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only, and not for purpose of limitation, the scope of the invention being defined in the claims.

I claim:

1. Apparatus for gauging and indicating the pressure in a pneumatic tire mounted on the retractable landing gears of an airplane comprising a shell connected to said airplane, a cylindrical member disposed within said shell and having a tire engaging member connected to the lower end thereof, said tire engaging member comprising a shank having a forked bracket pivotally connected thereto and said bracket having a roller rotatably mounted in its lower end, a compression spring of predetermined resistance disposed within the shell and adapted to urge the cylindrical member downwardly, a plurality of indicating incandescent bulbs each having an electric circuit leading therethrough, a plurality of contact points on said shell member disposed within the respective circuits leading through the incandescent bulbs, a contact member on the cylindrical member disposed so as to engage the respective contact members on the shell and to establish a circuit through one of the bulbs as the cylindrical member is moved by the tire engaging member, said landing gears having means for moving the same to retracted position and applying a force thereto which is greater than the resistance offered by said compression spring, whereby upon the tire engaging the wheel of the tire engaging member a variation in the air pressure of said tire will cause the tire engaging member to be moved upwardly an amount dependent on the air pressure in the tire thus moving the cylinder and its contact member within the shell and establishing a circuit to one of the bulbs to indicate to an operator the amount of pressure in said tire,

2. Apparatus for gauging and indicating one at a time, the amount of air pressure in the various tires mounted on a plurality of retractible landing gears in an airplane comprising movable means associated with each tire and engageable by the tire when it is moved to fully retracted position, an indicator having connection with the plurality of movable means, and means for establishing connection between the indicator and an individual movable means for a particular tire, said movable means comprising a shell connected to said airplane, a cylinder member disposed within said shell, a compression spring of predetermined resistance disposed within the shell and adapted to urge the cylinder member downwardly, a tire engaging member disposed on the lower end of the cylinder member, said tire engaging member comprising a shank having a forked bracket pivotally connected thereto and said bracket having a roller rotatably mounted in its lower end, said landing gears having means for moving the same to retracted position and applying a force thereto which is greater than the resistance offered by said compression spring, whereby upon one of the tires engaging the roller of a tire engaging member, a variation in the air pressure of said tire will cause the tire engaging member to be moved upwardly an amount dependent on the air pressure in the tire thus actuating the means for establishing connection between the indicator and an individual movable means for a particular tire, whereby the indicator will indicate the amount of air pressure in the selected tire.

THOMAS B. UPCHURCH, J R.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,087,979 Putman Feb. 24, 1914 1,156,862 Sibley Oct. 12, 1915 1,354,069 Terharr Sept. 28, 1920 1,581,320 Pumphrey, Jr Apr. 20, 1926 1,796,244 Courchesne Mar. 10, 1931 1,849,730 Morse Mar. 15, 1932 1,851,978 Dinger Apr. 5, 1932 2,358,370 Williams Sept. 19, 1944 FOREIGN PATENTS Number Country Date 116,915 Australia Apr. 28, 1943 645,607 France June 27, 1928 

